Coatings have been developed which exhibit excellent abrasion and corrosion resistance. These coatings have finely divided inert particles dispersed in a resin which is then mixed with a hardening catalyst and applied. The inert particles may be in the form of irregularly shaped granules or spherical depending upon the method of manufacture and may range in size from a few angstroms to several microns in diameter.
The resin is selected for its corrosion resistant properties and some commonly used include epoxy, polyester and vinyl ester resins. Ceramic is commonly used as the inert, but any other abrasion resistant compound may be used.
A coating commercially available is manufactured by Owens-Corning and marketed under the name Owens-Corning Abrasion Resistant Coating. The Owens-Corning coating contains 90% by weight finely divided ceramic particles dispersed in 10% by weight Bisphenol A epoxy resin. Additionally, a compound has been included which adds flexibility to the coating as applied.
The resin carrying the inert particles must be mixed with an appropriate hardening catalyst before application. Generally both the resin and catalyst are supplied from the coating manufacturer with instructions as to mixing.
When the epoxy and catalyst are mixed as received for the manufacturer, a highly viscous liquid is obtained. Such highly viscous liquid is difficult to apply evenly while covering the surface completely. Some manufacturers, such as Owens-Corning, do not recommend thinning with any solvent, leaving the applicator to determine how best to apply the coating. Without thinning, a coating of 25 mils is necessary to achieve a completely covered, i.e. holiday free, surface.
While experimentation may lead to the best solvent for thinning, there is no indication in the prior art indicating the effect by the thinner used on the final surface. The present invention relates directly to a combination of thinning solvent and curing which leads to a desired surface finish and coating qualities.
Surface preparation has been found to be critical in order to best retain the coating on the surface. Generally, sand blasting to white metal with sand, plastic grit, steel shot, garnet, or the equivalents is used, and some experimentation has been necessary to determine the necessary anchor pattern.
In addition to the use of a solvent, various additives can greatly enhance the qualities of the final product. Depending upon the requirements for the final product silicon dioxide can also be added in varying percentages as an addition to the resin and inert mixture, as can varying amounts of Novolac resins and polyglycol resins.